Survey - Airbox holes

[Gearhead]

OK, y'all, I'm looking for results here. Who out there has drilled holes in their VR airbox, and what were the results? How big and how many holes? Did you track mileage? Power impressions? Intake noise impressions? Did you leave it or put it back (tape over the holes)? Any other airbox mods?

 

I know the bike won't run w/o the airbox with the stock carbs. I know some dealers have made a standard practice of certain holes a certain way. I'm asking for YOUR results. I'm working on mine which I'll add soon. Any takers?

 

Jeremy

[ragamuffin]

Cut mine and gained 4 hp, but when the wind is at the wrong angle I get a whistle. tj

[Marcarl]

Drilled 4 x5\8" holes in the corneres of the lid, so that they're outside the filter. Can't say as that there seems to be any differnce. Course it runs fine without the air box as well, not quite as good but not a noticeable difference. She starts good, runs strong and I get about 280km \ 174 miles to the tank full, 15 liters = 3 1\4 Can gallons = 4 US gallons = 54 MPG in Canada and 43.5 in the warmer southern weather. Average speed is around 90-100 KPH or 55-60 MPH. Doesn't seem to matter much if I go faster, I just get there a little sooner and that's cuts in on riding time.

[Rick Butler]

Guys,

 

4 - 1/2" holes are all you need. One in each side corner of the top cover.

 

Rick

[Gearhead]

Cut mine and gained 4 hp, but when the wind is at the wrong angle I get a whistle. tj

 

TJ, can you 'splain? Did you dyno your bike? How did you cut your airbox? And does it whistle a tune, like Dixie?? :-)

 

4 - 1/2" holes are all you need. One in each side corner of the top cover.

 

Rick, have you done this? Was there any benefit, or did it just satisfy the urge many of us have to tinker? Did the engine get that mid-speed hesitation?

 

Course it runs fine without the air box as well, not quite as good but not a noticeable difference.

 

Carl, what do you mean? Have you ridden your bike with the airbox removed?

 

Thanks,

Jeremy

[Rick Butler]

Jeremy,

 

I have been using this method of releaving the vacumn in the air box since 1992, where I learned of this from a Canadian friend. They discovered there was a vacumn inside of the air box that was created from the carbs drawing more air than the opening in the top could accomodate. Four holes was what they found releaved that vacumn that allowed the carbs to breath better. And by using 1/2" holes, if this created a stumble or unwanted effect then a hole could easily be covered up with a patch of duct tape. But this really depends on the condition of your carbs and how old they are or if they have had the needles shimed, etc.

 

But you can see the effect of not allowing any restriction by taking the top off and the filter out and starting the bike. It should not like it where it should stumble when you try to give it throttle. This has created a very lean condition that can only be resolved by changing the needles to ones like the DynoJet Stage one or shimming them to where they come out more and dump fuel sooner. Plus this also upsets the design of the air box to allow the right flow into the carbs.

 

I have forgotten more than I care to about these 1st gen carbs, so I just answered your initial question.

 

Hope this helps,

 

Rick

[Marcarl]

I have not ridden my scoot with the airbox removed, but when I run it in a static situation it doesn't seem to effect it much if I take the box off or leave it on. As far as the 4 holes go, I'd honestly say I find not a noticeable difference, but then I don't drag race everyday and so require the utmost power output of the power palnt very often. This only happens when another 1st gen is in the area and I need to catch him, and if that happens than I always win.

[Gearhead]

This only happens when another 1st gen is in the area and I need to catch him, and if that happens than I always win.

 

Thanks Rick and Carl.

 

Jeremy